Activation of PKC depends on the availability of DAG, a signaling lipid that is tightly and dynamically regulated. DAG kinase (DGK) terminates DAG signaling by converting it to phosphatidic acid. Here, we demonstrate that DGKzeta inhibits PKCalpha activity and that DGK activity is required for this inhibition. We also show that DGKzeta directly interacts with PKCalpha in a signaling complex and that the binding site in DGKzeta is located within the catalytic domain. Because PKCalpha can phosphorylate the myristoylated alanine-rich C-kinase substrate (MARCKS) motif of DGKzeta, we tested whether this modification could affect their interaction. Phosphorylation of this motif significantly attenuated coimmunoprecipitation of DGKzeta and PKCalpha and abolished their colocalization in cells, indicating that it negatively regulates binding. Expression of a phosphorylation-mimicking DGKzeta mutant that was unable to bind PKCalpha did not inhibit PKCalpha activity. Together, our results suggest that DGKzeta spatially regulates PKCalpha activity by attenuating local accumulation of signaling DAG. This regulation is impaired by PKCalpha-mediated DGKzeta phosphorylation.
Pubmed ID: 12629049 RIS Download
Publication data is provided by the National Library of Medicine ® and PubMed ®. Data is retrieved from PubMed ® on a weekly schedule. For terms and conditions see the National Library of Medicine Terms and Conditions.
Cell line HEK293 is a Transformed cell line with a species of origin Homo sapiens (Human)
View all literature mentionsCell line NIH 3T3 is a Spontaneously immortalized cell line with a species of origin Mus musculus
View all literature mentionsCell line A-172 is a Cancer cell line with a species of origin Homo sapiens (Human)
View all literature mentions